Genetic and epigenetic alteration profiles for multiple genes in salivary gland carcinomas.

As combinations of genetic and/or epigenetic alterations occurring during salivary gland carcinogenesis are largely unknown, we here analyzed 36 salivary gland carcinomas (SGCs) for changes in INK4a/ARF, RB1, p21, p27, PTEN, p53, MDM2 and O6-MGMT genes using methylation specific PCR (MSP), loss of heterozygosity (LOH) assays and mutational analysis with immunohistochemistry (IHC), as well as histone H3 and H4 acetylation status. The RB1 gene was found to be the most frequently methylated (41.7% of cases), while methylation of p27(Kip1) and O6-MGMT were less frequent 8.

Frequent LOH on 22q12.3 and TIMP-3 inactivation occur in the progression to secondary glioblastomas.

Frequent allelic losses on the long arm of chromosome 22 (22q) in gliomas indicate the presence of tumor suppressor gene (TSG) at this location. However, the target gene(s) residing in this chromosome are still unknown and their putative roles in the development of astrocytic tumors, especially in secondary glioblastoma, have not yet been defined. To compile a precise physical map for the region of common deletions in astrocytic tumors, we performed a high-density loss of heterozygosity (LOH) analysis using 31 polymorphic microsatellite markers spanning 22q in a series of grade II diffuse astrocytomas, anaplastic astrocytomas, primary glioblastomas, and secondary glioblastomas that had evolved from lower grade astrocytomas.

Phosphorylation of FADD is critical for sensitivity to anticancer drug-induced apoptosis.

FADD has been shown to be phosphorylated at Ser194 at the G2/M transition of the cell cycle. Here we have investigated the contribution of this phosphorylation to apoptosis induced by anticancer drugs in two human prostate cancer cell lines, LNCaP and DU145. Both were arrested at G2/M and FADD was found to be phosphorylated at Ser194 on treatment with paclitaxel.

The molecular mechanism of sensitization to Fas-mediated apoptosis by 2-methoxyestradiol in PC3 prostate cancer cells.

It is widely known that death receptor Fas-dependent apoptotic signals are associated with development of prostate cancer, but the key pathways involved in sensitivity to the apoptosis remain unclear. Here we investigated the molecular mechanism by which 2-methoxyestradiol (2-ME) effectively sensitizes a human prostate cancer cell line, PC3, to Fas-mediated apoptosis. 2-ME significantly inhibited nuclear factor-kappaB (NF-kappaB) activation and downregulated Fas-associated death domain (FADD) protein interluekin-1beta-converting enzyme inhibitory protein (FLIP).

Genetic mapping of allelic loss on chromosome 6q within heterogeneous prostate carcinoma.

A number of genetic events have been reported in prostate carcinogenesis, including frequent loss of heterozygosity (LOH) on chromosomes 8q, 10q, 16q and 18q. In samples of heterogeneous, multifocal prostate carcinomas, we focused on chromosome 6q using PCR-based techniques with 15 microsatellite markers to identify the specific 6q deletion within tumors. LOH of one or more polymorphic markers was detected in 10 of 21 tumors (48%).

Distribution and secretory pathways of prostate specific antigen, alpha1-antichymotrypsin and prostate secretory granules in prostate cancers.

Using 19 radical prostatectomy specimens, we studied the histological distribution of free prostate specific antigen (PSA), total PSA, alpha1-antichymotrypsin (ACT) and prostate secretory granules (PSG) in both normal and cancerous cells of the prostate. After glutaraldehyde fixation, numerous fine eosinophilic droplets of PSG could be found mainly in the apical portions of normal acinous epithelial cells, but was markedly decreased in cancer cells. With antibodies against free PSA, normal acinous cells were granularly positive in the apical portion of the epithelium, which corresponded to the PSG, whereas cancer cells were diffusely positive.

Loss of heterozygosity on chromosome 6q correlates with decreased thrombospondin-2 expression in human salivary gland carcinomas.

Since loss of heterozygosity (LOH) on the long arm of chromosome 6q is frequently observed in salivary gland carcinomas, we examined 28 salivary gland carcinomas using 24 microsat- ellite markers mapping to 6q15-27 to identify the commonly deleted region that we felt might contain one or more tumor suppressor genes. LOH was detected in at least one locus in 10 of 28 tumors (35.7%).

Roles of p38- and c-jun NH2-terminal kinase-mediated pathways in 2-methoxyestradiol-induced p53 induction and apoptosis.

As 2-methoxyestradiol (2-ME), an endogenous estrogen metabolite, has been established to cause apoptosis of prostate cancer cells, the downstream effectors of the signaling remain unclear. In the current study, we investigated molecular mechanisms by which 2-ME induces apoptosis in human prostate cancer cell line, LNCaP. It was found that 2-ME mediates apoptosis through p53 induction.

Id proteins are overexpressed in human oral squamous cell carcinomas.

Background: The helix-loop-helix (HLH) proteins Id-1, Id-2 and Id-3 have been demonstrated to inhibit the activity of transcription factors and play an important role in regulating cell growth and tissue-specific differentiation.

Methods: To elucidate the involvement of Id in human oral squamous cell carcinoma (OSCC), we examined 83 surgical specimens and eight normal gingival mucosae for the expression of Id proteins by immunohistochemistry; in addition, some specimens of the OSCC and the normal gingivae were also examined for the expression of Id-1 mRNA by in situ hybridization (ISH), while Western blots were performed on six of the tumours and on cell lysates of five OSCC cell lines. We also explored the correlation between Id expressions and cellular proliferation indicating Ki-67 or clinical parameters.

c-Jun NH2-terminal kinase-dependent Fas activation contributes to etoposide-induced apoptosis in p53-mutated prostate cancer cells.

Background: The death receptor, Fas, has recently been demonstrated to contribute the chemotherapeutic agents-induced apoptosis, however, the detail mechanisms have yet to be fully understood, especially in prostate cancer cells.

Methods: PC-3 and DU145 stably transfected with dominant negative form of Fas-associated death domain (FADD) or specific kinase of c-Jun NH2-terminal kinase (JNK) (mitogen-activated protein kinase kinase, MKK7) were selected in the presence of hygromycin B (Hyg B). Cell viability was examined by (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphonyl)-2H-tetrazolium, inner salt (MTS) assay or flowcytometric analysis using green fluorescent protein (GFP).

Alterations of p14ARF and p16INK4a genes in salivary gland carcinomas.

The p14ARF and p16INK4a genes are localized to 9p21, where genetic alterations have been reported to be frequent in various human neoplasms. To elucidate their status in salivary gland tumorigenesis, we analyzed a series of 36 salivary gland carcinomas (SGCs) using methylation-specific PCR, differential PCR and immunohistochemistry. Homozygous deletion (3 cases) or methylation (7 cases) of p14ARF was detected in 10 (28%) SGCs, one and three showing co-deletion and co-methylation of both p14ARF and p16INK4a genes, respectively.

Requirement of c-jun for testosterone-induced sensitization to N-(4-hydroxyphenyl)retinamide-induced apoptosis.

Androgen stimulation strongly affects the sensitivity to anticancer drug-induced apoptosis in prostate cancer cells. We investigated the influence of androgen stimulation with testosterone on N-(4-hydroxyphenyl)retinamide (4-HPR)-induced apoptosis in the androgen-sensitive prostate cancer cell line LNCaP. Overexpression of a dominant negative form of mitogen-activated protein kinase kinase 7, a specific kinase of c-jun NH(2)-terminal kinase (JNK), significantly inhibited 4-HPR-induced JNK activation and apoptosis and canceled the hormone-dependent sensitization.

Novel tumor suppressor loci on 6q22-23 in primary central nervous system lymphomas.

Deletions on the long arm of chromosome 6 (6q) are one of the most common chromosomal alterations in systemic high-grade non-Hodgkin's lymphomas. However, the locations of allelic deletions and their roles have not yet been reported in primary central nervous system lymphomas (PCNSLs), most of which are classed as non-Hodgkin's lymphoma. We thus performed fine loss of heterozygosity (LOH) mapping of 6q in 29 samples of surgically resected PCNSLs using 39 microsatellite markers to identify commonly deleted regions.

Phosphorylation of Fas-associated death domain contributes to enhancement of etoposide-induced apoptosis in prostate cancer cells.

Fas-associated death domain (FADD) plays an important role as an adapter molecule in Fas (CD95/APO-1)-mediated apoptosis and contributes to anticancer drug-induced cytotoxicity. We treated three human prostate cancer cell lines with etoposide, a toposiomerase II inhibitor with activity against various tumors including prostate cancer. We found that the overexpression of FADD sensitizes etoposide-induced apoptosis through a rapid activation of c-Jun NH(2)-terminal kinase (JNK) and, subsequently, of caspase 3.

Contributions of mitogen-activated protein kinase and nuclear factor kappa B to N-(4-hydroxyphenyl)retinamide-induced apoptosis in prostate cancer cells.

The synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) has been shown to induce apoptosis in various types of tumors, including prostate cancer. We sought to examine the key mechanisms affecting the resistance to 4-HPR-induced apoptosis in three human prostate cancer cell lines, PC-3, DU145, and LNCaP. Concentrations of more than 40 microM 4-HPR produced apoptosis to almost the same extent in all cell lines; however, only the LNCaP line remained highly sensitive to concentrations less than 10 microM.

DNA hypermethylation status of multiple genes in prostate adenocarcinomas.

Multiple genetic mutations and epigenetic methylation are believed to be involved in prostate carcinogenesis, but it is not known whether these events are independent or correlated in some fashion. We therefore studied 32 prostate adenocarcinomas not only for deletions and / or mutations of multiple suspect genes, but also for aberrant DNA methylation using methylation-specific PCR (MSP). Of those genes examined, p16(INK4a), O(6)-MGMT, and GST-P were found to be the most frequently methylated (66%, 25% and 75% of cases, respectively), while methylations of p14(ARF), RB1, p21(Waf1), and p27(Kip1) were far less common (3%, 6%, 6% and 6% of cases, respectively).

Prediction of delayed neck metastasis in patients with stage I/II squamous cell carcinoma of the tongue.

Background: The incidence of delayed neck metastasis (DNM) in patients with squamous cell carcinoma (SCC) of the tongue is reported to be 20% to 50%. Although clinically negative cervical lymph nodes (N0) are associated with a good outcome, the prognosis is poor in patients with DNM. The aim of this study was to evaluate the clinicopathological and immunohistochemical parameters associated with DNM in patients with stage I/II SCC.

Heterogeneous methylation and deletion patterns of the INK4a/ARF locus within prostate carcinomas.

To elucidate the role of p53/p16(INK4a)/RB1 pathways in prostate carcinogenesis, we analyzed the p14(ARF), p16(INK4a), RB1, p21(Waf1), p27(Kip1), PTEN, p73, p53, and MDM2 gene status of multiple areas within 16 histologically heterogeneous prostate carcinomas using methylation-specific polymerase chain reaction, differential polymerase chain reaction, and immunohistochemistry. All focal areas examined had Gleason scores ranging from 1 to 5. Methylation of either PTEN or p73 was undetected in any sample, whereas expression of MDM2 seemed to be an independent event within small foci of 4 of 16 tumors.